In the railroad industry, a number of different monikers are used to refer to location where the tracks of a rail line cross a road or highway, including highway crossing, railway crossing, grade crossing, level crossing, and railway crossing, among others. For purposes of the present discussion, the term “highway crossing” will be used, although any of the terms commonly used in the railroad industry will apply equally well to the following discussion. Whatever the term used, highway crossings are familiar worldwide.
Highway crossings provide a significant hazard to vehicles and pedestrians on the intersecting highway or road, as well as to the trains and their crews, passengers, and cargo. In particular, a moving train cannot quickly stop or significantly reduce its speed in response to an obstacle on the track, such as a pedestrian or vehicle, given its mass. Hence, a ubiquitous strategy has developed over the many years in which the railroads have operated, namely, maintaining clear tracks in advance of oncoming trains.
Active highway crossings are very familiar, at least to those living in the United States. Generally, an electrical track circuit, which transmits either a DC or AC signal through a circuit formed by the pair of rails of the track itself, detects the wheels of a train entering the block or section of track on the approach to the highway crossing. Depending on the speed of the train and its distance from the crossing, an associated electrical control system then lowers crossing gates, activates flashing lights, and/or activates bells, depending on the particular system configuration. The control system is typically maintained within a housing or cabinet in the vicinity of the highway crossings.
Active crossing systems must occasionally be disabled, for example, for testing, maintenance, inspection, or repair or to allow work crews to repair or inspect the tracks adjacent the highway crossing without causing false or repeated activation of the gates, flashing lights, and/or bells. However, current techniques for disabling active crossing systems are complicated, and often involve placing physical jumpers across the correct terminals on the back of the electrical control system.
Another issue that has plagued the railroad industry since the inception of active crossings is railroad employees leaving a track/crossing out of service, releasing trains, and leaving the area. This leads to what is referred to by the Federal Railroad Administration (“FRA”) as a “Human Caused Activation Failure”, where a train traverses the crossing and the warning system does not activate because of human manipulation (e.g., railroad personnel took the active crossing system out of service). Such failures have resulted in serious accidents.